Various medical procedures require that one or more medical fluids be injected into the patient. Medical imaging procedures oftentimes involve the injection of a contrast media into the patient, possibly along with saline or other fluids. Other medical procedures involve injecting one or more fluids into a patient for therapeutic purposes. Power injectors may be used for these types of applications.
A power injector generally includes what is commonly referred to as a powerhead. One or more syringes may be mounted to the powerhead in various manners (e.g., detachably; rear-loading; front-loading; side-loading). Each syringe typically includes what may be characterized as a syringe plunger, piston, or the like. Each such syringe plunger is designed to interface with (e.g., contact and/or temporarily interconnect with) an appropriate syringe driver that is incorporated into the powerhead, such that operation of the syringe driver axially advances the associated syringe plunger inside and relative to a barrel of the syringe. One typical syringe driver is in the form of a ram that is mounted on a threaded lead or drive screw. Rotation of the drive screw in one rotational direction advances the associated ram in one axial direction, while rotation of the drive screw in the opposite rotational direction advances the associated ram in the opposite axial direction.
The syringes used by the power injector may be pre-filled and/or the power injector may be used to fill the syringes from one or more fluid containers (e.g., containers containing a single dose of medical fluid or bulk fluid containers containing multiple doses of a medical fluid). Pre-filled syringes may include plungers positioned distally relative to a nozzle of the syringe such that fluid may be contained within the syringe. Where fluid containers are utilized, the syringes may be interconnected to the powerhead in an empty condition and then filled by retracting the plunger of the syringe while the fluid container is fluidly connected to the syringe. Accordingly, syringes used in such systems may be supplied with plungers fully advanced (e.g., proximate to the nozzle of the syringe), fully retracted, or in any other appropriate position.